Ok, so we have downforce... what about lift?

This is just something that popped into my mind earlier today (I'm sure someone else has thought about it). So what do you get with down force, better handling at high speeds, better traction, better stopping distances and lower MPG. That's what I was thinking about, MPG (miles per gallon.. duh ) So what if you added lift to your car? Mount rear and front spoilers that add lift to your car and effectively reduce the weight of your car at high speeds, if enough lift is acquired. Sure it would ruin your handling and stability, but would this increase your mileage? Lets say a 2000+ mile road trip from California to Florida on the I-10. I have no plans or ambition to actually test this out, but I was just curious.

The weight of the car going down the road doesnt make much difference, the aerodynamics do.. Sure downforce causes drag, but so would lift. If you could make it neutral, however, I could see you gaining a little mpg.. In theory.